Excavator and hydraulic system thereof

Abstract

The utility model relates to an excavator and provides an excavator and a hydraulic system thereof in order to solve the problem of excavator rotation braking energy recovery, and the hydraulic system of the excavator comprises a rotation motor, a rotation control main valve, a rotation pump, a main pump, a detection device, a cut-off electromagnetic valve, a controller and the like. The detection device is used for detecting whether the rotary motor is in a rotary braking state; the cut-off electromagnetic valve is provided with an oil inlet correspondingly connected with two working oil ways of the rotary motor and an oil outlet connected with a pump opening output oil way of the main pump; the controller is electrically connected with the detection device and the cut-off electromagnetic valve and used for controlling on-off of the cut-off electromagnetic valve, and the rotary motor is provided with an oil supplementing oil way communicated with the oil return oil way. According to the excavator hydraulic system, rotation braking kinetic energy can be recycled to be used for other hydraulic executing parts of an excavator during rotation braking, and energy is saved.

Description

Technical Field

[0001] The utility model relates to an excavator, and more particularly to an excavator and a hydraulic system thereof. Background Art

[0002] An excavator consists of a lower body and an upper body that pivots and is mounted on the lower body. The power system, working device, and other components are mounted on the pivoting platform of the upper body, and its mass accounts for the majority of the vehicle's total weight. The upper body is driven by a swing motor. During operation, the excavator frequently activates and brakes its swing. Due to the upper body's enormous mass, activation requires significant energy. During braking, the upper swing energy is typically converted into heat through the hydraulic system and dissipated. This heat energy also requires energy to dissipate through the cooling system to prevent the hydraulic system from overheating. Therefore, for excavators, especially large ones, failure to recycle and reuse the swing braking energy results in significant energy waste and increased energy consumption. Utility Model Content

[0003] The technical problem to be solved by the utility model is the problem of recycling the rotary braking kinetic energy of an excavator, and an excavator and a hydraulic system thereof are provided to facilitate recycling the rotary braking kinetic energy of the excavator.

[0004] The technical solution for achieving the purpose of the present invention is as follows: a hydraulic system for an excavator is constructed, comprising a rotary motor, a rotary control main valve for controlling the rotary motor, a rotary pump connected to the rotary control main valve, and a main pump for supplying working pressure oil to hydraulic actuators other than the rotary motor; and further comprising:

[0005] A detection device for detecting whether the slewing motor is in a slewing braking state;

[0006] A cut-off solenoid valve has an oil inlet correspondingly connected to the two working oil circuits of the rotary motor and an oil outlet connected to the pump outlet output oil circuit of the main pump;

[0007] a controller, electrically connected to the detection device and the cut-off solenoid valve, and used for controlling the on and off of the cut-off solenoid valve;

[0008] The rotary motor has an oil replenishment passage communicating with the oil return passage.

[0009] In the hydraulic system of the excavator of the present invention, the controller is configured to control the cut-off solenoid valve to connect the high-pressure side working oil circuit of the swing motor to the pump port output oil circuit of the main pump when the swing motor is subjected to a swing brake.

[0010] In the hydraulic system of the excavator of the present invention, the detection device is an electric control handle electrically connected to the controller for performing a rotation operation, and the pilot hydraulic control end of the rotation control main valve is connected to an electric proportional valve electrically connected to the controller and used to control the rotation control main valve.

[0011] In the hydraulic system of the excavator of the present invention, the detection device further comprises a pressure sensor which is electrically connected to the controller and is configured to detect the pressure of the working oil connection port of the rotary motor.

[0012] In the hydraulic system of an excavator according to the present invention, the shut-off solenoid valve includes a hydraulically controlled reversing valve and a solenoid valve for controlling the hydraulically controlled reversing valve and electrically connected to the controller; the left and right oil inlets of the hydraulically controlled reversing valve are connected to the left and right working oil circuits of the rotary motor, respectively, and the oil outlet is connected to the pump outlet output oil circuit of the main pump. Furthermore, the hydraulically controlled reversing valve is a three-position three-way valve or a three-position four-way valve; in the neutral position, the left and right oil inlets are both cut off from the oil outlet; in the left position, the right oil inlet is cut off and the left oil inlet is connected to the oil outlet; and in the right position, the right oil inlet is connected to the oil outlet and the left oil inlet is cut off. The shut-off solenoid valve also includes a one-way valve; the oil outlet of the hydraulically controlled reversing valve is one-way connected to the pump outlet output oil circuit of the main pump via the one-way valve.

[0013] In the hydraulic system of the excavator of the present invention, the cut-off solenoid valve also includes a one-way valve, and the hydraulically controlled reversing valve is a two-position four-way valve. When in the left position, the right oil inlet and the right oil inlet are connected to the two oil outlets, and when in the right position, the right oil inlet and the oil outlet are all cut off from the two oil outlets; the two oil outlets are each unidirectionally connected to the pump port output oil circuit of the main pump through one of the one-way valves.

[0014] The technical solution for achieving the purpose of the present invention is as follows: constructing an excavator having the above-mentioned excavator hydraulic system.

[0015] Compared with the prior art, the hydraulic system of the excavator of the utility model can recover the kinetic energy of the rotary braking and utilize it in other hydraulic actuators of the excavator during the rotary braking, thereby saving energy. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 It is a schematic diagram of the hydraulic system of the excavator of the utility model.

[0017] Figure 2 This is the principle of the cut-off solenoid valve in the hydraulic system of the utility model excavator Figure 1 .

[0018] Figure 3 This is the principle of the cut-off solenoid valve in the hydraulic system of the utility model excavator Figure 2 .

[0019] Parts names and serial numbers in the figure:

[0020] Swing pump 1, main pump 2, swing motor 3, swing control main valve 4, controller 5, other hydraulic actuators 6, cut-off solenoid valve 7, hydraulically controlled reversing valve 71, solenoid valve 72, one-way valve 73, electric proportional valve 8, pressure sensor 9, left working oil circuit of swing motor 10, right working oil circuit of swing motor 11, main pump pump port output oil circuit 12, multi-way valve 13. DETAILED DESCRIPTION

[0021] The specific implementation scheme is described below with reference to the accompanying drawings.

[0022] like Figure 1 As shown, the excavator hydraulic system includes a swing motor 3, a swing control main valve 4 for controlling the swing motor 3, a swing pump 1 connected to the swing control main valve 4, a main pump 2 for supplying working pressure oil to other hydraulic actuators 6 other than the swing motor 3, a detection device, a cut-off solenoid valve 7 and a controller 5.

[0023] The detection device is used to detect whether the rotary motor 3 is in a rotary braking state. The rotary motor 3 has an oil replenishment circuit connected to the oil return circuit.

[0024] The shutoff solenoid valve 7 has an oil inlet correspondingly connected to the two working oil passages of the rotary motor 3 and an oil outlet connected to the main pump output oil passage 12 .

[0025] The controller 5 is electrically connected to the detection device and the cut-off solenoid valve 7 and is used to control the on and off of the cut-off solenoid valve 7. The controller 5 can determine the state of the rotary motor 3 according to the detection signal of the detection device and control the cut-off solenoid valve 7 according to the state of the rotary motor 3.

[0026] like Figure 1 As shown, in this embodiment, the swing hydraulic system includes an independent oil supply swing pump 1, which is connected to a swing control main valve 4. The swing control main valve 4 is connected to a swing motor 3 via two working oil circuits: a left swing motor working oil circuit 10 and a right swing motor working oil circuit 11. The swing motor 3 has an oil replenishment circuit connected to the return oil circuit. The return oil circuit directs low-pressure oil flowing out of the hydraulic actuator back to the hydraulic oil tank.

[0027] In an excavator, hydraulic actuators include not only the swing motor 3 but also a travel motor and various cylinders for driving the working devices. In this embodiment, these hydraulic actuators are collectively referred to as other hydraulic actuators 6. The pumps that supply the working pressure oil to these other hydraulic actuators 6 are collectively referred to as main pumps 2. The main pumps 2 can be a single hydraulic pump or multiple hydraulic pumps, each independently supplying pressure oil to its corresponding hydraulic actuator or merging oil circuits to supply oil to one or more hydraulic actuators.

[0028] When the slewing motor 3 is braking, the inertia of its load (slewing platform) drags the slewing motor 3 in reverse, causing the slewing motor 3 to function as a hydraulic pump during braking. One of the two working oil circuits connected to it is high pressure, and the other is low pressure. When the slewing motor 3 is braking, the controller 5 connects the working oil circuit on the high-pressure side of the slewing motor 3 to the main pump pump port output oil circuit 12. The slewing motor 3 outputs high-pressure oil to the main pump pump port output oil circuit 12, so that the pressure oil recovered by the slewing brake merges with the pressure oil output by the main pump 2, and is supplied to other hydraulic actuators 6 through the multi-way valve 13, thereby realizing the recovery and utilization of the kinetic energy of the slewing brake.

[0029] Optionally, in this embodiment, the detection device is an electric control handle (not shown) electrically connected to the controller 5 for performing a swing operation. The pilot hydraulic control end of the swing control main valve 4 is connected to an electric proportional valve 8 electrically connected to the controller 5 and used to control the swing control main valve 4. The operator controls the swing motor 3 by operating the electric control handle. During a swing or swing braking operation, the electric control handle outputs an electrical signal corresponding to its own swing direction and amplitude to the controller 5. Based on this electrical signal, the controller 5 outputs a control current to the electric proportional valve 8. The electric proportional valve 8 outputs pilot oil to control the operating position of the swing control main valve 4, thereby starting or braking the swing motor 3. During swing starting, the electric control handle swings from the center position to the corresponding lateral direction. Correspondingly, during swing braking, the electric control handle swings from the lateral direction back to the center position. Therefore, the controller 5 can also determine the state of the swing motor 3 based on the electrical signal from the electric control handle and then output a control current to shut off the solenoid valve 7 when the swing motor 3 is performing a swing braking operation, thereby recovering the kinetic energy of the swing braking.

[0030] Optionally, the detection device further includes a pressure sensor 9 electrically connected to the controller 5 and configured to detect the pressure at the working oil connection port of the swing motor 3. The magnitude of the swing braking kinetic energy is correlated with the excavator's swing braking acceleration. If the braking acceleration is low, such as when the swing is slightly decelerated, the hydraulic pressure generated in the working oil circuit of the swing motor 3 is low, and there is no hydraulic energy recovery value. This embodiment, by providing the pressure sensor 9, identifies situations in which there is brake kinetic energy recovery value during swing braking.

[0031] Optionally, the shutoff solenoid valve 7 includes a hydraulically controlled reversing valve 71 and a solenoid valve 72 electrically connected to a controller for controlling the hydraulically controlled reversing valve 71. The left and right oil inlets of the hydraulically controlled reversing valve 71 are connected to the left and right working oil circuits 10 and 11 of the swing motor 3, respectively, and the oil outlet is connected to the main pump output oil circuit 12. The solenoid valve 72 acts as a pilot valve to control the reversing of the hydraulically controlled reversing valve 71.

[0032] like Figure 2As shown, the hydraulically controlled reversing valve 71 is a three-position four-way valve. When in the middle position, the left oil inlet and the right oil inlet are both cut off from the two oil outlets. When in the left position, the right oil inlet and the right oil outlet are cut off, and the left oil inlet and the left oil outlet are connected; when in the right position, the right oil inlet and the right oil outlet are connected, and the left oil inlet and the left oil outlet are cut off. Furthermore, the cut-off solenoid valve 7 also includes a one-way valve, and the left oil outlet and the right oil outlet are each connected to the main pump outlet in a one-way direction through a one-way valve. Optionally, Figure 2 The three-position four-way valve can also be replaced by a three-position three-way valve, that is, the left oil outlet and the right oil outlet are replaced by one oil outlet. When the hydraulically controlled reversing valve 71 is in the left position, the oil outlet is connected to the left oil inlet, and when it is in the right position, it is connected to the right oil inlet. When it is in the middle position, the left oil inlet, the right oil inlet and the oil outlet are each cut off from each other.

[0033] In some embodiments, the cut-off solenoid valve 7 further includes a one-way valve 73, and the hydraulically controlled reversing valve 71 is a two-position four-way valve. Figure 3 As shown, when the solenoid valve 72 outputs pilot pressure oil to the hydraulic end of the hydraulically controlled reversing valve and is in the left position, the left oil inlet and left oil outlet of the hydraulically controlled reversing valve 71 are connected, and the right oil inlet and right oil outlet of the hydraulically controlled reversing valve 71 are connected. When the solenoid valve 72 does not output pilot pressure oil to the hydraulic end of the hydraulically controlled reversing valve 71 and is in the right position, the left oil inlet and left oil outlet of the hydraulically controlled reversing valve 71 are blocked, and the right oil inlet and right oil outlet of the hydraulically controlled reversing valve 71 are blocked. The left and right oil outlets each flow in a one-way direction to the main pump outlet oil circuit 72 via a one-way valve 73. During swing braking to recover braking kinetic energy, the hydraulically controlled reversing valve 71 is in the left position, and during swing operation, the hydraulically controlled reversing valve 71 is in the right position.

[0034] This embodiment also provides an excavator having the aforementioned excavator hydraulic system.

[0035] The working process of the excavator hydraulic system and the excavator rotary hydraulic system in this embodiment is as follows:

[0036] When the rotary motor starts to rotate, the electric control handle swings from the middle position to the side, and the controller 5 outputs control current to the electric proportional valve 8 according to the electrical signal of the electric control handle. The rotary control main valve 4 changes direction, and it delivers working hydraulic oil to the rotary motor 3 through the left working oil circuit 10 of the rotary motor. The rotary motor 3 rotates forward, and the low-pressure return oil of the rotary motor 3 flows back to the hydraulic oil tank through the right working oil circuit 11 of the rotary motor and the rotary control main valve 4.

[0037] When the slewing motor rotates forward and engages the slewing brake, the electric control handle returns to the center position, the slewing control main valve 4 returns to the center position, and the return oil circuit of the slewing motor 3 through the slewing control main valve 4 is cut off. Driven by load inertia, the slewing motor 3 operates in hydraulic pump mode. The oil in the slewing motor right working oil circuit 11 is increased by the oil output from the slewing motor 3. At this time, the controller 5 determines that there is value in recovering the kinetic energy of the slewing brake based on the electrical signals from the electric control handle and the pressure sensor 9. The controller 5 outputs a control current to the solenoid valve 72 in the cut-off solenoid valve 7, which switches the hydraulically controlled reversing valve 71, connecting the right slewing motor working oil circuit 11 with the main pump outlet oil circuit 12. The high-pressure oil output by the slewing motor 3 is then delivered to the main pump outlet oil circuit 12 through the cut-off solenoid valve 7. It then merges with the high-pressure oil output from the main pump 2 and is supplied to other hydraulic actuators 6, such as the boom cylinder, dipper cylinder, and bucket cylinder, thereby recovering and utilizing the kinetic energy of the slewing brake. While the swing motor outputs pressure oil under the drive of the load, the swing motor absorbs low-pressure oil from the oil return line and enters the swing motor.

Claims

1. An excavator hydraulic system comprising a swing motor, a swing control main valve for controlling the swing motor, a swing pump connected to the swing control main valve, and a main pump for supplying working pressure oil to hydraulic actuators other than the swing motor; characterized in that: Also includes: A detection device for detecting whether the slewing motor is in a slewing braking state; A cut-off solenoid valve has an oil inlet correspondingly connected to the two working oil circuits of the rotary motor and an oil outlet connected to the pump outlet output oil circuit of the main pump; a controller, electrically connected to the detection device and the cut-off solenoid valve, and used for controlling the on and off of the cut-off solenoid valve; The rotary motor has an oil replenishment passage communicating with the oil return passage.

2. The hydraulic system for an excavator according to claim 1, characterized in that: The controller is configured to control the cut-off solenoid valve to connect the high-pressure side working oil path of the rotary motor to the pump port output oil path of the main pump when the rotary motor is subjected to rotary braking.

3. The hydraulic system for an excavator according to claim 1 or 2, characterized in that: The detection device is an electric control handle electrically connected to the controller for performing a rotation operation, and the pilot hydraulic control end of the rotation control main valve is connected to an electric proportional valve electrically connected to the controller and used to control the rotation control main valve.

4. The hydraulic system for an excavator according to claim 3, characterized in that: The detection device further includes a pressure sensor electrically connected to the controller and configured to detect the pressure of the rotary motor working oil connection port.

5. The hydraulic system for an excavator according to claim 1, wherein: The cut-off solenoid valve includes a hydraulically controlled reversing valve and a solenoid valve for controlling the hydraulically controlled reversing valve and electrically connected to the controller; the left oil inlet and the right oil inlet of the hydraulically controlled reversing valve are connected to the left working oil circuit and the right working oil circuit of the rotary motor respectively, and the oil outlet is connected to the pump outlet output oil circuit of the main pump.

6. The hydraulic system for an excavator according to claim 5, characterized in that: The hydraulically controlled reversing valve is a three-position three-way valve or a three-position four-way valve. When in the middle position, the left oil inlet and the right oil inlet are both cut off from the oil outlet. When in the left position, the right oil inlet is cut off and the left oil inlet is connected to the oil outlet. When in the right position, the right oil inlet is connected to the oil outlet and the left oil inlet is cut off.

7. The hydraulic system for an excavator according to claim 6, wherein: The cut-off solenoid valve further includes a one-way valve, and the oil outlet of the hydraulically controlled reversing valve is unidirectionally connected to the pump outlet of the main pump through the one-way valve in the direction of the oil circuit output.

8. The hydraulic system for an excavator according to claim 5, characterized in that: The cut-off solenoid valve also includes a one-way valve. The hydraulically controlled reversing valve is a two-position four-way valve. When in the left position, the right oil inlet and the right oil inlet are connected to the two oil outlets. When in the right position, the right oil inlet and the oil outlet are all cut off from the two oil outlets. The two oil outlets are each unidirectionally connected to the pump outlet of the main pump through one of the one-way valves in the direction of the oil circuit output.

9. An excavator, characterized in that: A hydraulic system for an excavator according to any one of claims 1 to 8.

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